Misalignment correction

Misalignment correction

The significance of a patient’s mechanical leg axis in the development of cartilage damage—even leading to arthritic joints—has been known for some time. Before joint prosthetics became more widespread, osteoarthritis of the knee and ankle was most commonly treated by surgical correction of the mechanical leg axis. Misalignments involving an increased valgus or varus in the ankle can be congenital or arise after a fracture. The changed weight-bearing on the inside or outside of the joint can damage cartilage and lead to the development of osteochondral lesions, which, if left untreated, can then result in ankle arthrosis. To investigate a misalignment and overstressing, imaging (MRI and CT) must be performed for the entire standing leg, and sometime layered images are also required for a detailed analysis and planning of the correction. The angle of the joint must first be determined to ascertain in which bone (thigh, shin) the deviation is present and whether an opening (additive), a closing (subtractive), or a torsion correction is needed. If the misalignment is in the distal lower leg, a supramalleolar osteotomy is indicated. In complex cases, various corrections must be combined in order to restore correct weight-bearing. According to the treatment plan, the operation then corrects the defect with millimeter precision, and the result is secured with a plate. With the modern plate fixators now available, full weight-bearing is usually possible after four weeks, thus enabling a quick return to everyday life. After the osteotomy has healed, the patient is often able to achieve good athletic performance. All other necessary interventions such as ligament reconstruction or treatment of (osteo-) chondral lesions can be performed arthroscopically prior to the osteotomy. The relief this achieves allows damaged cartilage to regenerate and protects reconstructed ligaments. In the case of misalignment around the rear foot area with an increased valgus (rolling flat foot) or increased varus (high arches), heel bone osteotomy can effectively correct the misalignment. Any necessary tendon transplants can be performed in the same session to reinforce chronically insufficient tendons.